Reprinted with permission of the American Entomological Society from:
LaBerge, W. E., Bouseman, J. K. 1970. A revision of the bees of the genus Andrena of the Western Hemisphere. Part III. Tylandrena. Transactions of the American Entomological Society 96: 543-605.
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This small, slightly metallic species can be readily separated from all Tylandrena described above by the shiny galeae, the rather short maxillary palpae, the narrow facial foveae of the female, and the weak pronotal humeral angles and ridges as described below. It is similar to subtilis in the development of the labral process, though not as extreme, the moderately metallic integument, and the short vertex, but differs in the narrow facial foveae and small size.
FEMALE. MEASUREMENTS AND RATIOS. — N = 20; length, 10-12 mm; width, 3.0-3.5 mm; wing length, M = 3.95 ± 0.162 mm; FL/FW, M = 0.84 ± 0.006; FOVL/FOVW, M = 3.79 ± 0.050.
INTEGUMENTAL COLOR. — Black except as follows: mandible with apical half rufescent; flagellar segments 3-10 dark brown below; tegula reddish-brown; wing veins reddish-brown, membranes hyaline, very slightly infumate; terga distinctly metallic blue-green; sterna moderately rufescent; distitarsi dark reddish-brown.
STRUCTURE. — Antennal scape as long as first four flagellar segments or slightly longer; flagellar segment 1 equal in length to flagellar segments 2 and 3 plus half of 4; segment 2 about as long as 3 and each shorter than 4; segments 2 and 3 broader than long, 4-9 quadrate, 10 longer than broad. Eyes each about four times as long as broad, inner margins converging slightly towards mandibles. Malar space and mandible as in perplexa. Galea as in perplexa but shorter, rarely exceeding tip of galea by more than length of last segment, segmental ratio about 0.9:1.0:0.6:0.4 :0.4 :0.4. Labial palpus as in perplexa but ratio about 1.0:0.4:0.5 ; 0.4. Labral process as in subtilis but usually slightly thickened apicolaterally and occasionally slightly emarginate medially, apex of labrum without crista. Clypeus short, relatively flat, with minute punctures crowded subapically, sparser posteriorly (separated by more than one puncture width in posterior half), surface dulled by extremely fine tessellation. Supraclypeal area opaque, dulled by minute crowded punctures and shagreening. Genal area about one and one-half times as broad as eye in profile, dulled by minute sparse punctures and coarse, reticular shagreening. Vertex above lateral ocellus equals one ocellar diameter or less (if more, never more than nine-tenths of ocellus), opaque, finely tessellate. Face above antennae with coarse longitudinal rugae, interrugal punctures sparse, obscure. Facial fovea short, narrow, separated from lateral ocellus by more than one ocellar diameter.
Pronotum with humeral angle weak, triangular in lateral view, with dorsoventral ridge almost nonexistent and oblique suture weakly impressed, surface dull. Mesoscutum with minute punctures separated mostly by one-half to one puncture width, somewhat sparser posteromedially, surface opaque, dulled by fine dense tessellation. Scutellum similar but punctures sparser medially. Metanotum similar but punctures more crowded. Propodeum with dorsal enclosure with weak irregular rugulae mediobasally, tessellate; dorsal and posterior surfaces opaque, with well-separated, minute punctures and fine tessellation; corbicular surface moderately shiny, sparsely punctate and reticularly shagreened. Mesepisternum as in perplexa. Wing venation as in perplexa but second submarginal cell shorter. Tergum 1 with basal area punctures minute, sparse, surface dulled by fine reticulotransverse shagreening. Terga 1-4 with apical areas with distinct punctures in basal two-thirds or more, punctures separated mostly by one to two puncture widths (occasionally more crowded and sparser medially), surfaces moderately dulled by reticular shagreening. Terga 2-4 with basal area punctures minute, separated mostly by one to two puncture widths (occasionally less), surfaces moderately dulled by reticular shagreening. Pygidial plate V-shaped with small rounded apex, without raised internal triangular area. Sterna as in perplexa but sterna 3-5 with basal areas almost impunctate.
VESTITURE. — Generally pale ochraceous but darker on vertex and thoracic dorsum. Facial foveae with short dark brown hairs at least in upper half; a few long brown hairs surrounding foveae and on vertex. Terga without distinct apical bands but terga 2 and 3 with weak apical fringes at least laterally and tergum 4 with weak apical fringe across entire tergum. Corbicula with a few moderately long, plumose hairs anteriorly (occasionally absent), with abundant long simple internal hairs. Tibial scopal hairs largely simple, but along anterior and posterior margins weakly plumose. Inner surfaces tarsi yellow. MALE. MEASUREMENTS AND RATIOS. — N = 5; length, 9-10 mm; width, 2.5-3.0 mm; wing length, M(4) = 3.64 ± 0.542 mm; FL/FW, M = 0.76 ± 0.013; FS1/FS2, M = 1.71 ± 0.102.
INTEGUMENTAL COLOR. — Generally as in female but flagellar segments 3-11 dark brown below and wing membranes hyaline, colorless.
STRUCTURE. — Antennae moderately long, in repose reaching scutellum; scape length equal to first two and one-half flagellar segments; flagellar segment 2 shorter than 3, broader than long or quadrate, segments 3-11 longer than broad. Eyes each about three times as long as broad, inner margins converging slightly towards mandibles. Malar space as in female. Mandibles long, decussate. Galea as in female. Maxillary palpus as in female but segmental ratio about 0.9:1.0:0.6:0.6:0.5:0.6. Labial palpus as in female but ratio about 1.0:0.5:0.4:0.5. Labral process as in perplexa but not as long. Clypeus as in female but punctures more crowded. Supraclypeal area, genal area, face above antennae and vertex as in female.
Pronotum as in female but humeral angle ore pronounced. Thoracic sculpturing as in female except as follows: mesoscutal punctures distinctly sparser; propodeum with lateral surfaces opaque, sculpturing similar to posterior surface. Wing venation as in female. Tergal sculpturing as in female except as follows: Tergum 5 like female terga 2-4; terga 2-5 with basal areas often with punctures sparser and larger (more variable than in female); terga 1-5 with apical areas shinier. Sterna 2-5 extremely sparsely punctate shiny, reticular shagreening weak. Sternum 6 not sulcate medially.
Terminalia as figured (Figs. 66-70), not the following: sternum 7 with median emargination small, shallow, apical lobes broad; sternum 8 with apical part set off from basal part but without short stout median hairs, neck region short and slender.
VESTITURE. — Generally white or extremely pale ochraceous but with a few brown hairs alongside inner margins eyes and inner surfaces tarsi pale yellow. Terga without pale apical fasciae; tergum 2 with lateral patches of longhairs basally. Sterna with subapical fimbriae of long, extremely sparse hairs.
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